1. Field of the Invention
This invention relates generally to a system and method for providing control of vehicle steering and speed through an intersection and, more particularly, to a system and method for providing autonomous control of vehicle steering and speed through an intersection, where the intersection is defined as to whether it allows vehicle travel in certain lanes straight through the intersection, left turns, right turns, or combinations thereof.
2. Discussion of the Related Art
The operation of modern vehicles is becoming more autonomous, i.e., being able to provide driving control with less and less driver intervention. Cruise control systems have been on vehicles for a number of years where the vehicle operator can set a particular speed of the vehicle, and the vehicle will maintain that speed without the driver operating the throttle. Adaptive cruise control systems have been developed in the art where not only does the system maintain the set speed, but also will automatically slow the vehicle down in the event that a slower moving preceding vehicle is detected using various sensors, such as radar and cameras. Certain modern vehicles also provide autonomous parking where the vehicle will automatically provide the steering control for parking the vehicle. Some vehicle systems intervene if the driver makes harsh steering changes that may affect the vehicle stability. Some vehicle systems attempt to maintain the vehicle near the center of a lane on the road. Further, fully autonomous vehicles have been demonstrated that can drive in simulated urban traffic up to 30 mph, observing all of the rules of the road.
As vehicle systems improve, they will become more autonomous with the goal being a completely autonomous vehicle. For example, future vehicles probably will employ autonomous systems for lane changing, passing, turns away from traffic, turns into traffic, etc. As these systems become more prevalent in vehicle technology, it will also be necessary to determine what the driver's role will be in combination with these systems for controlling vehicle speed and steering, and overriding the autonomous system.
Vehicular ad-hoc network based active safety and driver assistance systems allow a wireless vehicle communications system, such as a dedicated short range communication (DSRC) system, known to those skilled in the art, to transmit messages to other vehicles in a particular area with warning messages about driving conditions. In these systems, multi-hop geocast routing protocols, known to those skilled in the art, are commonly used to extend the reachability of the warning messages, i.e., to deliver active messages to vehicles that may be a few kilometers away, as a one-time multi-hop transmission process. In other words, an initial message advising drivers of a certain situation is transmitted from vehicle to vehicle using the geocast routing protocol so that relevant vehicles a significant distance away will receive the messages where one vehicle's direct transmission range is typically relatively short.
Vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2X) communications systems require a minimum of one entity to send information to another entity. For example, many vehicle-to-vehicle safety applications can be executed on one vehicle by simply receiving broadcast messages from a neighboring vehicle. These messages are not directed to any specific vehicle, but are meant to be shared with a vehicle population to support the safety application. In these types of applications where collision avoidance is desirable, as two or more vehicles talk to each other and a collision becomes probable, the vehicle systems can warn the vehicle drivers, or possibly take evasive action for the driver, such as applying the brakes. Likewise, traffic control units can observe the broadcast of information and generate statistics on traffic flow through a given intersection or roadway.
When roads cross intersections are created. In order to prevent vehicles from colliding with each other at an intersection, some type of traffic control mechanism, such as stop signs, yield signs, traffic lights, etc., are provided so that perpendicularly or cross traveling traffic can navigate safely through the intersection. However, intersections, especially high traffic intersections, are still the cause of many traffic collisions. Further, because traffic traveling in one direction is generally stopped at busy intersections to allow traffic to flow in another direction, an intersection creates traffic congestion and frustration. Autonomously driven vehicles and controlled intersections offer an opportunity to safely and efficiently allow vehicles traveling in perpendicular or cross directions to safely navigate an intersection.
Enhanced traffic throughput safely at busy intersections with autonomous driving is technically challenging and an unresolved problem. Known techniques to accomplish this goal typically employ a central arbiter module, such as an intersection manager, to resolve space-time conflicts between vehicles and dispatch space-time reservations to communication equipped vehicles approaching the intersection. However, the practicality of such an arbiter module to resolve conflicts and reserve space-time slots in a timely manner is still unknown due to maintenance and operation issues of a computationally complex arbiter at traffic intersections.